projectile motion (1 Viewer)

[super.muppy]

A projectile has a time of flight and a range of 1200m calculate its maximum height ... i found its horizontal component to be 160 m.s^-1

thanks

 

[annabackwards]

range = UxT
So T = range/Ux = 1200/160 = 7.5s

So T for max height = 7.5/2 = 3.75s (due to symmetry in a parabola).

Now height = UyT + 0.5aT^2
Sub in the values (remember a = - 9.8 not + 9.8) and you'll get your answer

 

[super.muppy]

thanks andd.... the velocity with which it is projected ?

and
A cannonball is fired at 80m.s^-1 at an angle of 45 degrees to the horizontal. Calculate the hie=gt which the ball hits a vertical cliff 150 m away.

thanks

 

[inedible]

Horizontal velocity = 80Sin45
= 56.57m/s

Therefore it will reach the cliff in 150/56.57s
=2.65s

To calculate the height, we need the initial vertical velocity,
Vertical velocity = 80Cos45
= 56.57m/s

Using Displacement = Ut + At^2,
r = 56.57 * 2.65 + -9.8 * 2.65^2
= 81.09 m high

A quick tip, find out which values you need and which values you have will ensure you have the right formula, and do plenty of these projectile motion questions and you'll be fine!

 

[annabackwards]

Using the triangle thingo we find that
Ux = 80cos45 and Uy = 80sin45

Now Distance = UxT so T = distance/Ux = 150/80cos45

Now height = UyT + 0.5aT^2

So subbing in all values we get
Height = 80sin45 x 150/80cos45 + 0.5 (-9.8) (150/80cos45)^2
= whatever the calculator says

EDIT: Naww i got beaten to it

Using Displacement = Ut + At^2,
r = 56.57 * 2.65 + -9.8 * 2.65^2
= 81.09 m high

Should be Displacement = Ut + 0.5At^2

 

[Schoey93]

Are these problems you would be more likely to encounter in HSC physics or HSC mathematics?

 

[annabackwards]

Are these problems you would be more likely to encounter in HSC physics or HSC mathematics?

Both if you're referring to HSC 3U. I just assumed that the OP wanted physics answers because it'd be more likely seeing as projectiles is tauht very early in physics and much later in 3U

 

[ruchira2122]

loool HSC physics - it just tends to be very mathsy in the sense that applying formulas to a given situatuon is a big part of it.

are you doing it next year?

 

[annabackwards]

HSC physics - it just tends to be very mathsy in the sense that applying formulas to a given situatuon is a big part of it.

+1

To those wondering if they're going to do HSC physics, this is about as hard as the maths gets.

 

[Schoey93]

loool HSC physics - it just tends to be very mathsy in the sense that applying formulas to a given situatuon is a big part of it.

are you doing it next year?

I would like to, so maybe I will.

 

[Schoey93]

+1

To those wondering if they're going to do HSC physics, this is about as hard as the maths gets.

Good to know! I'll probably learn maths at university, either by myself or in an introductory mathematics class within a medicine, nursing or health sciences course.

It's funny though. I thought medicine required mathematics but I have not seen one course description (that I remember) say that it is assumed knowledge or recommended. Both UWS and UNSW recommend chemistry, but don't have it as assumed knowledge.

 

[Schoey93]

This maths is so easy! Is it true that HSC sciences are soft compared to other states? Obviously they are soft compared to IB sciences, but what about other states?

 

[annabackwards]

Good to know! I'll probably learn maths at university, either by myself or in an introductory mathematics class within a medicine, nursing or health sciences course.

It's funny though. I thought medicine required mathematics but I have not seen one course description (that I remember) say that it is assumed knowledge or recommended. Both UWS and UNSW recommend chemistry, but don't have it as assumed knowledge.

LOL yeah. I suggest doing HSC 2U maths though because it isn't that hard a course XD

This maths is so easy! Is it true that HSC sciences are soft compared to other states? Obviously they are soft compared to IB sciences, but what about other states?

Yep, Melbourne's VCE physics course is very maths orientated. Our HSC chem course does have a lot of calculations though.

 

[Schoey93]

Maybe I would do maths if I didn't have to do religion. Doing maths limits the amount of other, more appealing subjects I can do. I also don't want to do maths because my teachers don't make it very interesting generally.

That's interesting that the VCE course kept the heavy maths and the HSC course didn't. Some people might say it's a shame, but at least it has made physics more accesible for students. There are still many interesting concepts to learn, no doubt!

 

[annabackwards]

Maybe I would do maths if I didn't have to do religion. Doing maths limits the amount of other, more appealing subjects I can do. I also don't want to do maths because my teachers don't make it very interesting generally.

That's interesting that the VCE course kept the heavy maths and the HSC course didn't. Some people might say it's a shame, but at least it has made physics more accesible for students. There are still many interesting concepts to learn, no doubt!

Ah i see, fair enough

It might've made the subject more accessible, but it'd also make some kids who do physics believe they are capable of doing uni physics without an aptitude for maths =="

 

[youngminii]

:S
It's a pity that the Physics syllabus became so dumbed down
As Anna said, the projectile motion is probably the hardest maths you'll find in the HSC (albeit, it's almost always there).. They're not even worth that many marks either

You have to practice answering long response questions, which you'll have to do yourself or with a tutor to be honest
I know my school didn't teach us

 

[annabackwards]

:S
It's a pity that the Physics syllabus became so dumbed down
As Anna said, the projectile motion is probably the hardest maths you'll find in the HSC (albeit, it's almost always there).. They're not even worth that many marks either

You have to practice answering long response questions, which you'll have to do yourself or with a tutor to be honest
I know my school didn't teach us

Yeah, i wish there was more maths. Then physics would probably scale higher *shakes fist*

I would've been able to practise long response questions at school if i didn't get my dodgy teacher... but yeah you'll probably have to do them with yourself or with a tutor

 

[super.muppy]

Yeah, i wish there was more maths. Then physics would probably scale higher *shakes fist*

I would've been able to practise long response questions at school if i didn't get my dodgy teacher... but yeah you'll probably have to do them with yourself or with a tutor

isint it still good in terms of scaling or am i wrong ?

 

[annabackwards]

isint it still good in terms of scaling or am i wrong ?

It's still good in terms of scaling but it could also be much better XD